EP0899029A2 - Rolling stand for rolling strips - Google Patents

Abstract

I- Working rolls (13a, 13b) and intermediate rolls (12a, 12b) have annular recesses (15a, 15b; 16a, 16b) in one end surface between roll journals (18a, 18b; 17a, 17b) and roll barrels. During rolling, working rolls and intermediate rolls are displaced so that above and below the strip (14) being rolled there is at least one roll with its annular groove in the strip edge zone.

Description

The invention is based on a roll stand for rolling strips straightened, with work rolls that rest on backup rolls Support intermediate rolls, the work rolls and / or the Back-up rolls and / or the intermediate rolls against each other axially are arranged displaceably and wherein at least the Work rolls and / or the intermediate rolls one over the Entire roll length extending curved or have a cylindrical contour.

When rolling strips of different widths is for that Usually reaching the desired flatness goal Adjust the crowning of those responsible for flatness Work rolls required. The change in crowning takes place in such a way that with decreasing bandwidth the The crown of the work roll must be increased. This results from the increasing supportive effect of the intermediate or Back-up rolls next to the strip edges of the rolling stock, which makes the Work rolls are bent next to the belt edges, what only by a corresponding increase in the crowning of the Work rolls can be compensated with decreasing bandwidth can.

Due to the bending of the work rolls it comes in Strip edge area of the rolling stock with a decrease in thickness edge sharpening of the rolled strip. For this is in addition to the bending of the work rolls also the decay of the elastic deformations caused by the rolling load the work rolls in the unloaded area next to the rolling stock with responsible. The better the friction between the rollers and the rolling stock and the thinner the work rolls are to this change in the thickness of the strip occurs more suddenly. Each the tighter the rolling stock and the thicker the work rolls, the more so the drop in thickness from the strip edges is greater.

State of the art is the different Crowning requirements for the flatness of the strips and for Avoid edge sharpening by axially displaceable To meet rollers, so the entire crown area with just one roller or a pair of rollers.

For example, EP 0049798 B1 proposes the work rolls with a curved contour that extends over the entire Bale length of both rollers runs and which has a shape in which the two bale contours are only in a relative axial position of these rollers complementary complete. This allows the shape of the roll gap and so that the cross-sectional shape of the rolled strip is small Paths of displacement of the rollers having the curved contours influence and thus also an influence on the Apply edge pressure and prevent this Reduce edge sharpening.

However, at the same time with this strip edge influence treatment of the entire band also takes place. For The load distribution is evened out in EP 00 91 540 B1 suggested both the work rolls as well Back-up rolls and possibly the intermediate rolls over the entire Bale length with a bottle-shaped, S-shaped contour provided that consist of a convex and a concave Area and which has a shape in which the bale contours are mutually supportive or interacting rollers only in one certain relative axial position of these rollers complementary supplement (CVC technology). All rollers are axial slidably arranged. By relative axial displacement of the Rolling any pair of rollers can thus the contour of Nip can be influenced sensitively. The disadvantage, that flatness of the belt and the edge pressure be influenced at the same time is familiar with this Roll stand but also still available.

Another way, the adverse effect of Compensating roll deflection is described in DE 36 37 206 C2 described for a four-high rolling mill. The proposed solution consists in forming a backup roller such that the undesirable deflections caused by the rolling load can be compensated automatically by the backup roller massive axial inner part, the core shaft, and an outer Has peripheral part in the form of a sleeve, and wherein between Inner part and outer peripheral part at each end of the backup roller generally cylindrical cavities open to the outside are arranged. This measure will bend under the Roll load the free end of the sleeve opposite to that Direction in which they would normally turn if there would be no voids by the amount that is essentially equal to the deflection of the core wave, so that the contact surface between the work roll and the Tape material remains essentially flat.

A measure that does not have an even more direct effect is not Pre-published patent application (application no. 19626565.7) described. To make the strip thickness even To achieve the edge area, the work rolls with the Provide axially concentric notches, which results in a different flattening behavior of the with the notches provided roller body to itself subsequent full body results. At the belt edges there is a larger flattening due to the lack of internal support due to the notches (Voids) that equalize the strip thickness in Width direction.

The object of the invention is from this known prior art Starting technology, a rolling stand of the generic type too create with the simultaneously and independently of each other Profile and flatness of belt edge and belt center also at bands of different widths are simple influence and the strip edge pressure and Have the edge sharpening reduced.

The task set is due to the characteristic features of claim 1 solved in that the work rolls and Intermediate rolls on one of their end faces, in the between the journal and the surface of the roller extending area around the axle journal ring-shaped have running recesses.

Advantageous embodiments of the invention are in the Subclaims specified.

Since according to the invention both on the work roll level as also on one side of the intermediate roller level are provided with an annular recess, these opposite with respect to work and intermediate roll are arranged is an optimal weakening of the Supporting effect of the support rollers next to the belt edges can be achieved. Because in the area of the belt edges are above and below the rolling stock one end of the bale that through an annular recess just a weaker support allowed. These measures will not make the work rolls so strongly bent around the band and the crowning area for the desired flatness target of narrow and wide Bands severely restricted. A constant overlap of the There is no recess with the tape for this effect required. It is therefore sufficient to use the work roll to provide a base crown to match the axial Shifting the work rolls as well as with an actuator Work and intermediate roll bending the desired flatness for to reach the middle of the band. The basic crowning is according to the Invention through the area of the recesses not interrupted, but continued across this area.

With a belt edge-oriented driving style of the work rolls and / or the intermediate rolls can additionally the profile and the flatness of the belt edge is favorable in the desired sense to be influenced.

The annular recesses according to the invention can be in their shape and size arbitrarily chosen and thus the to rolling strips can be optimally adjusted. It is after an advantageous embodiment of the invention possible, annular recesses for the intermediate rolls choose which in shape and size from the Cut-outs in the work rolls differ.

Further advantages, details and features of the invention result from the explanations for one in one illustrated schematic drawing figure Embodiment as well as various diagrams.

Fig. 1

ein Sexto-Walzgerüst gemäß der Erfindung,

Fig. 2

ein Diagramm des Walzspaltprofils für ein Sexto-Walzgerüst nach dem Stand der Technik,

Fig. 3

ein Diagramm des Walzspaltprofils für ein Sexto-Walzgerüst gemäß der Erfindung,

Fig. 4

ein Diagramm des Walzspaltprofils für ein Sexto-Walzgerüst gemäß der Erfindung,

Fig. 5

ein Diagramm der Lastverteilung Arbeitswalze/Zwischenwalze für ein Sexto-Walzgerüst nach dem Stand der Technik,

Fig. 6

ein Diagramm der Lastverteilung Arbeitswalze/Zwischenwalze für ein Sexto-Walzgerüst gemäß der Erfindung.

Show it:

Fig. 1

a six-high mill stand according to the invention,

Fig. 2

2 shows a diagram of the roll gap profile for a six-high roll stand according to the prior art,

Fig. 3

2 shows a diagram of the roll gap profile for a six-high roll stand according to the invention,

Fig. 4

2 shows a diagram of the roll gap profile for a six-high roll stand according to the invention,

Fig. 5

a diagram of the load distribution work roll / intermediate roll for a six-high rolling mill according to the prior art,

Fig. 6

a diagram of the load distribution work roll / intermediate roll for a six-high mill stand according to the invention.

Figure 1 shows schematically the roller arrangement of a Sixth scaffolding (10) with two work rolls (13a, 13b), two Intermediate rollers (12a, 12b) and two backup rollers (11a, 11b).

The work rolls (13a, 13b) and the intermediate rolls (12a, 12b) are each one-sided at one of their roller ends provided annular recess (15a, 15b, 16a, 16b) and so arranged that these recesses (15a, 15b, 16a, 16b) above and below the rolling stock (14) with respect to Work rolls (13a, 13b) and the intermediate rolls (12a, 12b) opposite each other in the area of the band edges.

With the upper roller set, the support effect in the Area to the left of the belt edge through the ring-shaped recess (15a) the work roll (13a) and in the area to the right of Band edge through the annular recess (16a) of the The intermediate roller (12a) is reduced and the work roller (13a) is not so strongly bent around the band (14). The same applies to the lower roller set, the rollers of which compared to the upper Roll set are arranged rotated by 180 °.

In the following Figures 2 to 6 is clear from diagrams made what results with the rollers according to the invention can be achieved, with each on the abscissa Width is given in mm; the ordinates of FIGS. 2 to 4 indicate the crown in mm, in FIGS. 5 and 6 the Rolling force in kN / mm.

In Figure 2, the roll gap profile (shown symmetrically) for a six-high mill stand with solid rollers throughout the state of the art for two tapes of different widths applied. The crown of the work roll was included 0.1418 mm chosen so that for the wide band (width = 1600 mm) sets a rectangular roll gap profile (20). At the same crowning of the work rolls, however, results in a narrower band (width = 1000 mm) an unsatisfactory Roll gap profile (21) with a parabolic flatness error of 162 µm, which is characterized by an increased crowning of the Work rolls of 0.493 mm would have to be compensated.

FIG. 3 shows the same strip widths and the same rolling load 1 with a roller arrangement according to the invention resulting symmetrical roll gap profiles applied. in the Both rollers have one in the area of the cutouts Shell thickness of 65 mm and the rollers are in this example shifted against each other so that the reason for the recess for both bandwidths with the band edges (overlap Ü - 0). The work roll crown was used in this example With 0.0418 mm chosen so that here too for the wide Belt (width = 1600 mm) again a rectangular roll gap profile (22) sets. But also for the narrower band (width = 1000 mm) is now almost a rectangular cross section (23) for the Roll gap profile achieved with an undesirable parabolic Errors of only 15.4 µm, less than a tenth of the parabolic error with the full rolls. This little one Errors can be solved with the help of e.g. B. the Work roll bend to be eliminated, it is not another Sanding with greater crowning of the work rolls is necessary.

In Figure 4, the roll gap profiles for the wide strip (24) and for the narrower band (25) for another example applied. With otherwise the same setting as that 3 are now the for both bandwidths Work rolls shifted so that the recess reason Overlaps with the tape over a length of 15 mm (Overlap Ü = 15 mm). The intermediate roll position remained unchanged. From Fig. 4 it is now clear how in addition the Band edge with regard to "Edge Drop" at a suitable one Displacement of the work roll is affected. For the there is no beneficial effect on the flatness millimeter-precise positioning of the work roll recesses required, especially about the positioning of the Intermediate roller cutouts are another setting option consists.

Thus, the limited to the band edge area allows Freedom of positioning an individual influence on the Band edge in terms of flatness and profile (edge drop). It is thus possible with the roller arrangement according to the invention, Profile and flatness independent of belt edge and belt center from each other by appropriate shift of work or the intermediate rollers.

Lift the two other diagrams of Figures 5 and 6 again the advantage of the invention over the known State of the art with roll stands, in which full rolls are used. Because the bale edge of the Intermediate roll (full roll) within the backup roll barrel is shifted, it occurs in the area of this shifting edge a sudden drop in load with the consequence of undesirable Markings on the rollers. 5 is the load distribution between work roll and intermediate roll of such Roll stand applied over the roll width, with the clearly sharp drop in load at the right end of the curve (26).

When using rollers with the invention There are annular recesses in the area Sliding edge, since here the "softer" roller part with its Cutout acts to a flatter load drop like that corresponding diagram of FIG. 6 with its curve (27), which drops more gently to the right, can be seen. This flat load drop has a gentler effect on the rollers and does not lead to unwanted markings.

Claims (6)

Roll stand for rolling strips with work rolls, which are supported on support rolls via intermediate rolls, the work rolls and / or the support rolls and / or the intermediate rolls being arranged axially displaceable relative to one another and at least the work rolls and / or the intermediate rolls being one over the entire roll length extending curved or cylindrical contour, characterized in that the work rolls (13a, 13b) and the intermediate rolls (12a, 12b) each on one of their end faces, in which there is between the axle journal (17a, 17b, 18a, 18b) and the roll surface extending area around the axle journals (17a, 17b, 18a, 18b) have annular recesses (15a, 15b, 16a, 16b). Roll stand according to claim 1, characterized in that the contour of the roll shell outer sides in the region of the annular recesses (15a, 15b, 16a, 16b) is a continuation of the contour of the roll part with a full cross-section. Roll stand according to claim 1 or 2, characterized in that the shape and size of the annular recesses (15a, 15b) of the work rolls (13a, 13b) from the shape and size of the annular recesses (16a, 16b) of the intermediate rolls (12a, 12b) deviates. Roll stand according to one or more of claims 1 to 3, characterized in that the work rolls (13a, 13b) and the intermediate rolls (12a, 12b) are offset from one another and axially displaced such that both strip edges of the rolling stock (14) are in the area the annular recesses (15a, 15b, 16a, 16b) of the work rolls (13a, 13b) and the intermediate rolls (12a, 12b) offset by 180 ° with respect to the work rolls (13a, 13b). Method for rolling strips of different widths in a roll stand (10) according to one or more of the preceding claims, characterized in that the axial displacement of the work rolls (13a, 13b) and the intermediate rolls (12a, 12b) is carried out so that always above and at least one of the rolls (12a, 12b, 13a, 13b) with its ring-shaped recesses (15a, 15b, 16a, 16b) is arranged below the rolling stock (14) in the edge region of the rolling stock (14). Method for rolling strips according to claim 5, characterized in that the axial displacement path of the work rolls (13a, 13b) is different in length from the axial displacement path of the intermediate rollers (12a, 12b).

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